Flywheel and mounting method for same

Abstract

In order to suppress axial vibration in a crank system, prevent knocking sound, and reduce vibration noise, a flywheel ( 1 ) which is mounted onto the crankshaft of an engine (E) is made into a spoked form having an uneven number of spokes ( 5 ). This prevents the symmetrical bending that occurs with an even number of spokes, and divides the vibration mode in the peripheral direction. It is preferable that the number of spokes be seven. The flywheel ( 1 ) is mounted such that, when the pistons of predetermined cylinders # 5 and # 6 are at top dead center at the start of the expansion stroke, one of the spokes ( 5 a ) is positioned on the opposing side to these predetermined cylinders, which border the center of the crank (C).

What is claimed is: 
     
       1. An engine assembly comprising:
 an engine having pistons associated with cylinders; 
 a crankshaft; and 
 a flywheel having an uneven number of spokes, 
 wherein the flywheel is mounted on the crankshaft such that a spoke is substantially in alignment with, and opposed to, a predetermined one of the cylinders when the piston associated with the predetermined cylinder is at top dead center at the start of an expansion stroke. 
 
     
     
       2. The assembly according to  claim 1 , wherein the number of said flywheel spokes is seven. 
     
     
       3. A method for mounting a spoked flywheel onto the crankshaft of an engine, the engine having pistons and cylinders, the method comprising the steps of:
 placing said flywheel on the crankshaft; 
 orienting a spoke of said flywheel substantially in alignment with, and opposed to, a first predetermined cylinder when the piston of a first predetermined cylinder is at top dead center at the start of the expansion stroke. 
 
     
     
       4. The assembly of  claim 1 , wherein the engine is a V-6 engine and the predetermined cylinder is the cylinder closest to the flywheel. 
     
     
       5. The assembly of  claim 1 , wherein the flywheel is mounted on the crankshaft such that a second spoke is substantially in alignment with a second predetermined one of the cylinders when the piston associated with the second predetermined cylinder is at top dead center at the start of an expansion stroke.